Many liquid crystal display devices that make use of the optical anisotropy (Δn) (hereinafter, referred to as “Δn” in some cases) or the dielectric constant anisotropy (Δ∈) (hereinafter, referred to as “Δ∈” in some cases), which are features of a liquid crystal compound, have been manufactured and have been used in watches, calculators, measurement instruments, instrument panels for vehicles, word processors, electronic diaries, portable telephones, printers, computers, TVs and so on. A liquid crystal compound used in liquid crystal display devices has a specific liquid crystal phase, and the phase mode thereof can be roughly divided into a nematic phase, a smectic phase and a cholesteric phase. Among these, a nematic phase is most widely used. Further, among display modes and driving systems, which are used in the display devices, as the display mode, a dynamic scattering mode (DS mode), a guest/host mode (GH mode), a twisted nematic mode (TN mode), a super-twisted nematic mode (STN mode), a thin-film transistor mode (TFT mode), and a ferroelectric liquid crystal mode (FLC mode) have been developed. As the driving systems, a static driving system, a multiplex driving system, an active matrix driving system, a two-frequency driving system and so on have been adopted. Recently, three kinds of the TN mode, STN mode and TFT mode are in a mainstream. A liquid crystal material used in any of display devices is necessary to be stable to moisture, air, heat, light and so on, in addition thereto, to show a liquid crystal phase in a temperature range as broad as possible around room temperature, have appropriate dielectric constant anisotropy (Δ∈) and refractive index anisotropy (Δn), be fast in the response speed, and be drivable at a low voltage. In order to satisfy these characteristics, a liquid crystal that is low in the viscosity and low in the threshold voltage is necessary. At the present time, as a single compound, there is no substance that can satisfy all the conditions mentioned above. Accordingly, liquid crystal compounds from several kinds to several tens kinds are mixed to obtain required characteristics. Further, for displays for high-definition TVs, 3D adaptable TVs and so on, a further improvement in the response speed is in demand.
There are many proposals also of a nematic liquid crystal composition that uses a cyclohexane compound and is excellent in the responsiveness. For example, a nematic liquid crystal composition that is large in a pretilt angle to be formed, remarkably low in the generation rate of stripe/domain, chemically stable, drivable at a low voltage and excellent in the high speed responsiveness capable of responding to a high time-sharing drive (patent document 1), and an anti-ferroelectric liquid crystal composition that is a novel cyclohexane compound that provides a nematic liquid crystal composition that is wide in an operative temperature range with respect to a magnitude of desired birefringent, and excellent in the responsiveness and contrast, and provides liquid crystal display devices such as TN-LCDs, STN-LCDs, TFT-LCDs and so on which use the nematic liquid crystal composition and are improved in the electrooptical properties, and is improved in the response speed from an antiferroelectric state to a ferroelectric state (patent document 2) can be cited. Further, there is a material of a liquid crystal display cell, which has a cyclohexane ring and, when mixed with a liquid crystal composition being generally used at the present time, does not shown an increase in the viscosity and can effectively reduce the threshold voltage (patent document 3). However, all proposals until now are unsatisfactory in the response speed.